Magnetic clutch



SeptL1 7,1946. A. M. MMCAL 'LU'M 2,407,757

MAGNETIC CLUTCH Filed Dec. a, 1943 .JNVENTOR.

ATTQRIVEY ALI M IW lector rings and brushes.

Patented Sept. 17, 1946 UNITED STATES PATENT OFFICE- Bendix Aviation Corporation, Tet-erboro, N..J.,

a corporationof Delaware Application December 8, 1943, Serial No. 513,421

or otherwise mounted on the drive shaft for longitudinal movement, and is energized from a source of power connected thereto through col- The collector rings and brushes are subject to Wear and corrosion after continueduse and exposure to conditions, so that they must be watched and replaced to insure proper actuation of the clutch, while the splined or -keyed mounts forthe drive. face of the clutch, unless they inter'fi-t perfectly, will cause lost motion in a radial direction, when the clutch faces are coupled to provide driving torque.

To insure proper clutch actuation independent of such conditions, va novel clutch arrangement is hereby devised, whereby brushes, collector rings, splines, keys and the like are eliminated by fastening the drive clutch member'to the drive shaft by a longitudinally flexible member responsive to longitudinal thrust and/or pull to provide for longitudinal shifting of one clutch :member to provide for clutching the said driving and driven members together for driving torque without splines or keys. ticular utility in automatic. pilot systems for mobile objects because of its rugged construction and its instantaneous couple, which eliminates lost motion andautomatie release action provided for in the drive shaft connection to the clutch face about to be described in detail. Furthermore, because each clutch means is separate and independent of thecoil, either may be readily replaced without disturbing the coil as in the prior art.

Accordingly, one object of the present invention is to provide novel means for joining the clutch drive plate with the drive shaft whereby lost motion resulting from "worn or poorly machined splines, key connections and the like such as usually used between the drive shaft and the clutch face associated therewith, is eliminated.

Another object ofthe present invention is to provide a clutch construction, which is relatively simple to manufacture and one in which the clutch plates may be readily demounted and replaced, and which because of its ruggedness and simple construction is particularly suitable and safe for use with automatic pilot systems for aircraft.

Another object is to provide a novel magnetic l clutch, whereby brushes, collector rings or the like are rendered unnecessary.

Another object is to provide a novel magnetic clutch including a novel automatic release arrangement. 7

Such an arrangement has par 3 Claims, (01.1-92-84) A further object 'i's'to provide a novel improve- 'ment in magnetic clutches, whereby a pair of coupling elements are concentrically mounted on drive and driven shafts "extending within "a stationary coil, so as to thereby automatically :release and couple in response to E. M. F. .produced in the coil without the use of frictional electric contacts asso'ciatedwith'the clutch memhers-or their shaft means. I

Another object is to provide in an electromagnetic -clutch, 'apair of coupling members comprising clutching faces of unlike non-magnetizable material to thereby prevent sticking when the clutch is deener'gized.

The above and other objects and advantages of the present invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawing wherein several embodiments of the invention are illustrated. It' is to be expressly understood, however, that the drawing is for the purpose of illustration only and is not designed as a definition of the limits of the invention. Reference for this latter purpose should be had to the appended claims.

In the drawing, wherein like reference char- -a'ct-ers refer to like parts throughout the several views,

Figure 1 is a side sectional view of the .novel clutch and surrounding coil of the present invention.

Figure -2 is an end View of the structure of Figure 1 looking from the drive shaft toward the spring deelutching means.

Figure 3 is aside elevation of the clutch memb'erswi'th a diagrammatic illustration of the coil circuit.

Figure 4 is a plan view of one form of dia'- phrag-m =or spider designed to provide for declu'tching the drive and driven members.

Figure 5 is a plan View of another form of spider designed for the purpose of declutching the members. i

Figure dis a plan View of another former spider designed for the purpose of declutching the members.

Figure? is a plan view of another form of spider designed for the purpose of declutching the members.

Figure 8 is a plan view=of another form of spider "designed for the purpose of declutching the memof spiderdesigned for the purpose of declutching the members. Figure 10 is a plan view of another form ofspider designed forthe purpose of declutching the members.

Referring now to the drawing for a detailed no description of the present invention, and first with particular reference to Figure 1, numeral l represents a coil concentrically mounted around two clutch members II 'and I 2, which may be formed of magnetic material of which one or both of the faces l3 and I4 may be of nonmagnetic material, preferably unlike material.

Clutch member II is connected to the drive shaft l5 through a flexible spring means, such as metallic diaphragm l6.

Diaphragm I6 may include corrugations l1 around a non-corrugated axial center portion l8, riveted, welded or otherwise suitably secured to the end of drive shaft I5, and similarly secured to the back of clutch member II at a non-corrugated annular area It at its perimeter.

The clutch member I l is provided with face I3,

of non-magnetic material such as aluminum or the like and may be designed as a ring with an annular countersunk portion 20 to allow for any thrust from the drive shaft or flexing of the diaphragm spring l6.

.Clutch member [2 is secured to the driven shaft 2|, as an integral part thereof or by other suitable means and faces member H within the confines of coil [0, which connects through leads 22 and 23, shown in Figure 2, to a suitable power source for energization.

When the coil Ill is energized, movable clutch member II is magnetically attracted to longitudinally fixed magnetic clutch member I 2, which may if desired have a non-magnetic clutch face [4 preferably of material unlike that of face 13, whereby any sticking from lagging magnetic flux is eliminated. Longitudinal movementof clutch member ll into'engagement with clutch member [2 is made againstthe resiliency cf the flexible spring diaphragm l6, which is moved forward from a normally aligned on center declutched position, so that face [3 of clutch member I l contacts with fixed clutch face M to provide driving couple. a

When the coil I 0 i deenergized the clutch members are parted by the return action of spring diaphragm US, which automatically returns to. normal on center declutched position.

As shown in the several Figures 4 through 10, numerous forms of diaphragms, spiders or the like for declutching the parts may be provided.

In Figure 4 the spider member comprises a corrugated disc with a level, plane or flat non-corrugated center surface l8 anda level, plane or fiat non-corrugated rim or annular area H! at its perimeter as hereinbefore described. Each surface l8 and I9 may be provided with rivet or screw holes for attachment to the end of drive shaft and the rear peripheral edge of clutch member ll.

In Figure 5 is shown another form of spring disc of wheel-like design including an annular fiat'rim 25, a central fiat hub 26 and a plurality of radially extending corrugated spokes 21.

Figure 6 shows a further form of spring disc, wherein there i provided a flat rim 28, a central annular flat ring 29 and tangentially curving or spiral spokes 30, curving around from the central ring 29, so as to tangentially merge into the outer rim 28. a

Figure 7 illustrates another form of disc, wherein there is provided an outer annular fiat rim 3|, a concentrically mounted apertured inner flat ring 32 with two diametrically opposite or aligned radially extending lugs or arms 33 and 34, each outer end of which is formed into arcuate loops, such as 35 and .36, and centrally merged at each 4 outer portion with the inner edge of the annular rim 3| with lugs or arms 33a.

Figure 8 illustrates a further form, of disc, wherein no continuous or annular outer rim is provided, but rather a rim comprising a plurality of spiral or tangentially radiating corrugated arms 31 with spaced segmental or arcuate flat rim sections 31a extending from a centrally apertured annular. flat .plate 38.

Figure 9 shows still another form of disc construction, wherein a plate 39 having a flat annular rim 39a and a fiat central surface or plate 391), is corrugated therebetween and apertured at desirable points to provide maximum flexing value, such as the half-moon openings 40.

Figure 10 is a further form of disc construction wherein a plate 4| is apertured as at Ma, so as to form a rim 42, with relatively wide off-center spokes 43.

Although several embodiments of the invention have been illustrated and described, changes and modifications, which will now appear to those skilledin the art, may be made without departing from the scope of the present invention. Referenceis, therefore, to be had to the appended claims for a definition of the limits of the present invention,

I claim:

1. In a magnetic clutch having a pair of opposed clutch members adapted to be arranged within a surrounding coil, a driven shaft connected at one end to one clutch member, a drive shaft, the other clutch member being in the form of a ring having a side recess at its inner periphery, and a resilient drive coupling comprising a corrugated plate secured at its central portion to an end of the drive shaft and to one side face of said ring adjacent its perimeter to thereby normally hold said ring clutch member spaced from the other clutch member and through flexing of the plate to permit the. clutch members to move toether. V

2. A magnetic coupling comprising, coaxial drive and driven shafts, opposing clutch members of magnetic material for each of said shafts, one of said members being annular in form, a resilient -member having a flat hub portion and a flat peripheral; portion, the hub portion being fixed to one of said shafts, the peripheral fiat portion being fixed to. the outer peripheral face of said annular'clutch'member, the other of said clutch members being fixed to the other of said shafts: a coil surrounding both of said clutch members, said members being confined within the two 5 planes defined by the outer edges of said coil;

and means to energize said coil.

3. A magnetic coupling comprising, coaxial drive and driven shafts, opposing clutch members of magnetic material for each of said shafts, one

0 of said members being annular in form, at least one of the opposing faces of said clutch members being of non-magneticmaterial; a resilient member having a flat hub portion. and a flat peripheral portion, the hub portion being fixed to one 5 of said shafts, the peripheral fiat portion being fixed to the outer peripheral face of said annular clutch member, the other of said clutch members being fixed to the other of said shafts; a coil surrounding both of said clutch members, said mem- O bers being confined within the two planes defined 1 by the outer edges of ergize-said coil.

ALAN M. MACCALLUM.

other said coil; and means to en- 

